diff --git a/core/lib/Drupal/Core/CoreBundle.php b/core/lib/Drupal/Core/CoreBundle.php
index 16faeef..b4b4290 100644
--- a/core/lib/Drupal/Core/CoreBundle.php
+++ b/core/lib/Drupal/Core/CoreBundle.php
@@ -358,7 +358,7 @@ protected function registerTwig(ContainerBuilder $container) {
         // This is saved / loaded via drupal_php_storage().
         // All files can be refreshed by clearing caches.
         // @todo ensure garbage collection of expired files.
-        'cache' => TRUE,
+        'cache' => settings()->get('twig_cache', TRUE),
         'base_template_class' => 'Drupal\Core\Template\TwigTemplate',
         // @todo Remove in followup issue
         // @see http://drupal.org/node/1712444.
@@ -366,10 +366,8 @@ protected function registerTwig(ContainerBuilder $container) {
         // @todo Remove in followup issue
         // @see http://drupal.org/node/1806538.
         'strict_variables' => FALSE,
-        // @todo Maybe make debug mode dependent on "production mode" setting.
-        'debug' => TRUE,
-        // @todo Make auto reload mode dependent on "production mode" setting.
-        'auto_reload' => FALSE,
+        'debug' => settings()->get('twig_debug', FALSE),
+        'auto_reload' => settings()->get('twig_auto_reload', NULL),
       ))
       ->addMethodCall('addExtension', array(new Definition('Drupal\Core\Template\TwigExtension')))
       // @todo Figure out what to do about debugging functions.
diff --git a/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php b/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php
new file mode 100644
index 0000000..003d61e
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/Theme/TwigSettingsTest.php
@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Theme\TwigSettingsTest.
+ */
+
+namespace Drupal\system\Tests\Theme;
+
+use Drupal\simpletest\WebTestBase;
+use Drupal\Component\PhpStorage\PhpStorageFactory;
+
+/**
+ * Tests Twig engine configuration via settings.php.
+ */
+class TwigSettingsTest extends WebTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('theme_test');
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Twig Settings',
+      'description' => 'Tests overriding Twig engine settings via settings.php.',
+      'group' => 'Theme',
+    );
+  }
+
+  /**
+   * Ensures Twig template auto reload setting can be overridden.
+   */
+  function testTwigAutoReloadOverride() {
+    // Enable auto reload and rebuild the service container.
+    $this->settingsSet('twig_auto_reload', TRUE);
+    $this->rebuildContainer();
+
+    // Check isAutoReload() via the Twig service container.
+    $this->assertTrue(drupal_container()->get('twig')->isAutoReload(), 'Automatic reloading of Twig templates enabled.');
+
+    // Disable auto reload and check the service container again.
+    $this->settingsSet('twig_auto_reload', FALSE);
+    $this->rebuildContainer();
+
+    $this->assertFalse(drupal_container()->get('twig')->isAutoReload(), 'Automatic reloading of Twig templates disabled.');
+  }
+
+  /**
+   * Ensures Twig engine debug setting can be overridden.
+   */
+  function testTwigDebugOverride() {
+    // Enable debug and rebuild the service container.
+    $this->settingsSet('twig_debug', TRUE);
+    $this->rebuildContainer();
+
+    // Check isDebug() via the Twig service container.
+    $this->assertTrue(drupal_container()->get('twig')->isDebug(), 'Twig debug enabled.');
+    $this->assertTrue(drupal_container()->get('twig')->isAutoReload(), 'Twig automatic reloading is enabled when debug is enabled.');
+
+    // Override auto reload when debug is enabled.
+    $this->settingsSet('twig_auto_reload', FALSE);
+    $this->rebuildContainer();
+    $this->assertFalse(drupal_container()->get('twig')->isAutoReload(), 'Twig automatic reloading can be disabled when debug is enabled.');
+
+    // Disable debug and check the service container again.
+    $this->settingsSet('twig_debug', FALSE);
+    $this->rebuildContainer();
+
+    $this->assertFalse(drupal_container()->get('twig')->isDebug(), 'Twig debug disabled.');
+  }
+
+  /**
+   * Ensures Twig template cache setting can be overridden.
+   */
+  function testTwigCacheOverride() {
+    theme_enable(array('test_theme_twig'));
+    variable_set('theme_default', 'test_theme_twig');
+
+    $cache = array();
+    // Prime the theme cache.
+    foreach (module_implements('theme') as $module) {
+      _theme_process_registry($cache, $module, 'module', $module, drupal_get_path('module', $module));
+    }
+
+    // Load array of Twig templates.
+    $templates = drupal_find_theme_templates($cache, '.html.twig', drupal_get_path('theme', 'test_theme_twig'));
+
+    // Get the template filename and the cache filename for
+    // theme_test_template_test.html.twig.
+    $template_filename = $templates['theme_test_template_test']['path'] . '/' . $templates['theme_test_template_test']['template'] . '.html.twig';
+    $cache_filename = drupal_container()->get('twig')->getCacheFilename($template_filename);
+
+    // Navigate to the page and make sure the template gets cached.
+    $this->drupalGet('theme-test/template-test');
+    $this->assertTrue(PhpStorageFactory::get('twig')->exists($cache_filename), 'Cached Twig template found.');
+
+    // Disable the Twig cache and rebuild the service container.
+    $this->settingsSet('twig_cache', FALSE);
+    $this->rebuildContainer();
+
+    // This should return false after rebuilding the service container.
+    $new_cache_filename = drupal_container()->get('twig')->getCacheFilename($template_filename);
+    $this->assertFalse($new_cache_filename, 'Twig environment does not return cache filename after caching is disabled.');
+  }
+
+}
diff --git a/sites/default/default.settings.php b/sites/default/default.settings.php
old mode 100644
new mode 100755
index 8dbb5a7..0531e00
--- a/sites/default/default.settings.php
+++ b/sites/default/default.settings.php
@@ -284,6 +284,41 @@
 $settings['update_free_access'] = FALSE;
 
 /**
+ * Twig debugging:
+ *
+ * Display debugging information in comments surrounding Twig template output
+ * and automatically recompile templates whenever the source code changes.
+ *
+ * @see http://drupal.org/node/1906392
+ *
+ * Not recommended in production environments (Default: FALSE).
+ */
+# $settings['twig_debug'] = TRUE;
+
+/**
+ * Twig auto-reload:
+ *
+ * Automatically recompile Twig templates whenever the source code changes. If
+ * you don't provide a value for twig_auto_reload, it will be determined based
+ * on the value of twig_debug.
+ *
+ * Not recommended in production environments (Default: NULL).
+ */
+# $settings['twig_auto_reload'] = TRUE;
+
+/**
+ * Twig cache:
+ *
+ * By default, Twig templates will be compiled and stored in the filesystem to
+ * increase performance. Disabling the Twig cache will recompile the templates
+ * from source each time they are used. In most cases the twig_auto_reload
+ * setting above should be enabled rather than disabling the Twig cache.
+ *
+ * Not recommended in production environments (Default: TRUE).
+ */
+# $settings['twig_cache'] = FALSE;
+
+/**
  * External access proxy settings:
  *
  * If your site must access the Internet via a web proxy then you can enter